docs: def get_subject(self, identifier):
          """
          Build a Subject XML block for a SAML 1.1
          AuthenticationStatement or AttributeStatement.
          """
          subject = etree.Element('Subject')
          name = etree.SubElement(subject, 'NameIdentifier')
          name.text = identifier
          subject_confirmation = etree.SubElement(subject, 'SubjectConfirmation')
          method = etree.SubElement(subject_confirmation, 'ConfirmationMethod')
          method.text = self.confirmation_method
          return subject